Contraction expansion joint



' Aug. 23, 1927.

, 1,639,763 A. c. nscH R CONTRACTION EXPANSION JOINT Filed Dec. 7.,1925

Patented Aug. 23, 192 7.

I ALBER T O. FISCHER, OI CHICAGO, ILLINOIS.

oon'rnae'rron nxrsnsron JOINT.

Application filed December 7, 1925. Serial No. 73,932.

Heretofore contraction joints employed for the separation of slabs in paving have consisted in either continuous sheets or plates acting as a separating plate, or they 5 have had a tongue and groove arrangement so that in pouring concrete against either side of the plate a tongue and groove arrangement would be formed. Later it has been suggested that the plate be embodied in the'concrete and the space between the plate and the surface of the concrete be allowed. to break upon the setting of the concrete. 7

There are a number of-i'objections to the separating plate as heretofore used, as it has never been provided with perforations for reinforcing rods, and, therefore, could not lock the slabs together. Reinforcing rods in winter are subject to extreme brittleness, and such brittleness is more likely to cause a break in. the upward pressure of the slab. Likewise the tongue which is embodied in the groove formed by the plate after the concrete cracks vertically downward, 1s

'25 just as apt to crack directly thru the tongue,

because of the brittleness of the concrete, andv it is very questionable whether the tongue of the sizes permitted in the depth of the concrete as laid under the present method, upon continuous shock, whether the thiclmess would be suflicient to prevent the tongue breaking off or breaking thru, thus destroying the utility of the contraction.

plate and making it of no more service than asmall plate that had the reinforcing rods extended therethru. a I

My invention consists of a combination of a straight, vertical plate, or a straight, yertical expansion j oint," which primarily econ- 40 omizes in sheet material, and is, therefore,

more economical in cost.

No ver satisfactory tongue and groove joint can e made by the use of asphalt expansion material because of the ductility of 46 the material, butby the use of a straight slab, having the edges reinforced, such material' may readily be utilized. e I

In connection with these separating plates 1- use pins three/or four inches in thickness,

50 in the nature of dowelsil-as distinguishedfrom reinforcing rods. T e pins are so constructed thereof. V

I do not discard the reinforcing bar-thru the perforated .plate, but utilize 1t as here- -wise treated to make them that the grain runs lengthwise tofore, but I claim that the use of the wooden dowels of the dimension cited are free from brittleness in winter and that they would resist'the upward pressure of the concrete to greatervadvantage than the tongue made out of the concrete itself or the brittle bars of steel.

PA E QFITJ/ICE These dowels may be creosoted or otherwaterproof, and I depend upon them to function in place of the tongue and groove, using the reinforcing rods for strengthening, but which are not manufactured three inches in diameter, or of such large dimensions, and it would be necessary to utilize steel shafting or something of that k1nd, wh1ch would not be very practical, and which would not have the resistance that the wood dowels of the sizes mentioned would have in functioning as a locking means between concrete slabs.

Very often reinforcing bars when being unloa ed from tra cars or being handled by merely dropping t em from a given height are shattered and broken. Th1s is due to lack of ductility and often due to temperature conditions. e

It can readily be conceived that any heavy trucks passing over concrete slabs at the point of interlocking must exert a tremenous jar orshock whenpassing over one slab to the other, especially when five or six ton trucks pass over said pavement. It is my belief that many of the tongueand groove bars would be broken under such conditions, which would be more severe than in throwing reinforcing bars from gondola cars on properly treated with waterproofing taken together with the reinforcingstrips or rods,

having the 'wooden dowels-act in the place of the tongue and groove formation, would be very superior to the similar use of f, and 1" reinforcin bars. Likewise, the i'esiliency 'of this woo would take up the shock 'at the surface of the pavement to better advantage than concrete against concrete mere- 1y separatedby an iron plate.

To further illustrate my invention I refer to Fig. 1, in which instance a preformed expansion joint is utilized with reinforcing strips alongthe upper and lower edges, in which a represents the 'mastic material from which expansion joints are usually ing the perforations for the lar e manufactured, brepresents the reinforcingstrips for the upper and lower edges, 0 represents the perforations for the, large wooden dowels, and -d the perforation for'the steel reinforcing bar.

In Fig. 2 I show a metal plate in which grepresents the metal which ranges from a 14 to EZO'gauge sheet, --c representwooden dowel pin, and -Z the perforation for the reinforcing bar. 1

Fig. 3. This illustration represents a reinforcing bar made out of steel employed in concrete construction, which in itself, especially at low temperatures, becomes very brittle and can readily be broken by striking it against other steel, -e represents the steel bar.

V Fig. 4 illustrates the large wooden dowel pin which takes the place of the tongue of one slab nesting into the roove of another slab made of concreteand formed by steel plates shaped in accordance with the'tongue and oove arrangement desired. This dowel pin 1s preferably formed with a shoulder that the penetration of the plate will be limited and fixed the distance that the wood will penetrate either concrete slab. The

wooden dowel pin is illustrated by fthe dimension preferably being three or more inches in diameter. The shoulder need not necessarily be provided although it is preferred.

Fig. 5 illustrates a reformed expansion joint in which the various parts are assembled preparatory to casting the concrete on either side and over the top, a-- represents the expansion joint material, b the reinforcing strips on the upper and lower edges of the preformed joint, c representing the larger perforation for the dowel pin -f, and -d representing the perfora- I, tion for the reinforcing bar e.

poured against the and pouring concrete on either side that the wooden dowel pins would function to greater advantage than a strip or tongu groove extending in a direct line witl;

It may be readily understood that upon] the cleavage .formed by the upper flange the plates heretofore used.

F1g.- 6 illustrates a section of concrete plate, which in this inate -g showing the stance is a metal p large perforations -0- for the dowel pin '-f-- extending on either side of the plate into the concrete, the concrete being partially removed to expose the dowel ins to vlew, the concrete -h complete y surround these dowel .pins and, therefore, preventing any raising of the slabs at these points.

' It ran readily be understood that heavy trafiic passing over the surface of this mass would not impart the shock to the dowel pins --f-- when prepared out of wood that it would to the steel reinforcing rods shown in-lfiig. 5 at -e-.

,"Figure 7 illustrates a concrete mass h and one side of the plate, the concrete completely removed from the right hand. side of the plate, showing the metal plate -g with the concrete mass -hover the metal, plate, the wood dowel 'f extendin and embodied in the concrete mass, to the le as shown by the dotted lines -z'- for the dowel pin and 7' for the reinforcing rod.

It can readily be conceived that the flush, straight contact formed by the steel plate without interference, will make a better joint and a stronger joint where the large WOOdGII'dOWel pins .are utilized than where a brittle substance is entirely employed.

My invention relates particularly to the fact that in the employment of the wooden dowel pin as shown in concrete, a much securer joint can be made, and the joint will not be liable to rupture as there would be no brittleness of the material, such as is imparted by nature to a concrete mass and to steel, such as is used in construction work.

I, therefore, use a material which is not brittle by nature, which is more resilient and which is not subject to frost penetration, in combination with a separating means which divides the concrete and joins it to gether by a non-brittle substance. The separating plate may be made out of "any material, viz, an expansion joint, a metal plate or a wooden board, as any one of them would function, when submerged in concrete,'to form a break in that part of the concrete which is above .the separating means= By the use of a preformed expansion joint the crevice will remain more waterproof than in the case where a metal plate is utilized solely, which ultimately will raise out, or where a wooden board is used, unless the board is properly treated there may be'a possibility of decay.

I prefer that the large wooden dowels em- 'ployed for joints in concrete slabs be treated with-a waterproof material or creosoted, and it is essential that the grain of the wood run lengthwise thereof so that the strain upon the dowel will be counter-to the direction of the grain of the wood. Likewise that the stronger woods be employed, such as, oak, hickory, maple and the like.

It may be readily understood that this look and separating means need not necessarily be confined to pavin but will act likewise in the locking toget er of sections of concrete stadiums, Wall sections, viaduct sections, and many other types of construction where it is desirable to utilize a separating meansand locking means to prevent movement in the respective abutting sections.

' I claim:

1. A joint between concrete sections, comprising a vertically disposed separating strip aving wooden dowels projecting from opposite sides thereof, the dowelsoli one side of the strip having a diameter greater than 5 that of the diameter of the same dowels projectili from the opposite side of the strip. 2. joint between concrete sections, comprising a vertically disposed separating strip .having wooden dowels projecting from opposite sides thereof, the dowels on one side of the strip having a diameter greater than that of the diameter of the same dowels projecting from the opposite side of the strip, and metal reinfol ring rods projecting thru 15 the plate intermediate the dowels and alternating therewith throughout the length of the strip. 1

3. The combination as set forth in claim 1, and in which the separating strip comprises a preformed strip of compressible material.

4. The combination as set forth in claim 2, and in which the separating strip comprises a preformed strip of compressible material.

5. The combination-as set forth in claim 1, and in which the separating strip comprises a preformed stri of compressible material having a reinforcing strip upon the crown thereof;

6. The combination as set forth in claim 2, 30

and in which the wparating strip comprises a preformed strip of compressible material having a reinforcing strip upon the crown and base.

Signed at Chicago, Illinois, this 27th day 35 of November, 1925.

' ALBERT G. FISCHER. 

